Analysis of the ion Composition in the Io Plasma Torus From Observations by the New Horizons Mission

Sammanfattning: The object of this project is to analyse data from the plasma torus around Jupiter. The material in the plasma supplied by Jupiter’s moon Io is composed mostly of the elements oxygen and sulphur at different ionisation states and the torus has a changing environment. The goal is to analyse the composition of the torus and calculate the ratios between the two elements as well as the ions of each element and compare it to previously done research.The images that are analysed were taken by the spectrograph Alice on board the space probe New Horizons, during its flyby of Jupiter in 2007. The images were taken in the range of 520 - 1870 Å. The atomic database CHIANTI is used to simulate a spectrum and compare it with the data from the New Horizons mission and calculate the ratios.The analysis of the spectrum shows that the ratio of oxygen to sulphur in the Io plasma torus was lower in 2007 than previously seen, as well as a higher O+ to O++ ratio than has been found in previous studies. This may be the result of the volcanic eruption of Tvashtar the same day as the data was gathered.